Transmission Swap Mishaps

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RanchWelder

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Jan 14, 2023
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Location
Earth
First Name
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Truck Year
87
Truck Model
Blazer
Engine Size
355ci
The GM 205 is divorsed... the case cover is different than the Ford or the Dodge which is NOT divorsed.
My 208 had the auto locks and they are available for anyone who needs them as good known to be working cores.
Shifting into low and getting stuck is usually from the plastic shifter fork tabs breaking or mis-matched tire sizes.

When you force it into gear, with smaller front tires than the rear, you can break the tabs and end up stuck trying to force the transfercase back out of gear. If the tires are significantly different, your entire drive line is trying to slip the smaller tires, so the larger tires can control the differnetials, which are now mis matched. A 1-1/2 to 2% difference in diamter, can break stuff under the wrong conditions in 4wd.

If your tires are all the same size... disregard this answer.

The Suburban got stuck in 4-Low so I had it towed back to the shop. When I went to pick it up a tooth in the rear diff seems to have broken and now needs replacement. Might the shop have mis-installed the tranny or driveline to cause that gear to break? And do I need to change the hubs? Should I put auto hubs on my '79?
The first sentence concernes me... How did they tow it? Front end or rear?
Did they get it out of frozen low gear before they towed it? Beacuse if they did not, and they towed it from the rear, your front locks engaged, in low gear, than the torque the entire length of the driveline, trying to rotate your rear axle, could have broken stuf, depending how fast they towed you.

If the tow truck moved abruptly foreward, then backwards before they lifted it, or while they were manuvering, with everything locked up, it could have broken your diff. Usually the u-joints would break first...

If somebody accidentally smashed the rear yoke inwards, while it was being installed or the trans was being pulled out/replaced, then your crush washer was ruined and your differential is toast from alignment, not a broken tooth.
Broken rear gear could mean the entire rear axle is ruined.

A little humming, it's a bad bearing and needs a rebuild.
Stuff gets broken inside a diff, where I'm from, it goes to the bad dogs back yard.
The bearing races get cracked and warped. Large metal chunks ruin the inner tollerances, fast.
Lots of Gov Locker's ruined lots of rear axles.

The tow could have ruined it... twisting or rotating the truck, while locked up, with a front tow, could have broken stuff, if the rear end has a locker and it was still engaged.
Did you frag your Gov Locker?
 
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